On trains in Sri Lanka you hear men marching the corridors chanting, ‘Wadiwadiwadiwadi.’

They are advertising these wonderful snacks, which are perfect accompanied by a cold beer. Push a prawn into each cake before frying for a delicious treat. You’ll need to start preparing these the night before you want to eat them.

• Drain the beans or lentils and place in a bowl with everything but the flour and the oil. Stir well with a wooden spoon. Gradually add the flour, a handful at a time, followed by a splash of water, and mix. Keep adding the flour and water until the mixture comes together and holds its shape when you press a handful of it together.

• With wet hands, take a tablespoonful of the mixture at a time, shape it into a ball and then flatten into a disc about 2cm thick. Place the discs on a dampened plate while you heat the oil.

• Half-fill a heavy-based pan with oil and put over a medium heat. Test the heat of the oil with a chunk of bread; when the bread sizzles and gently turns golden in 30 seconds, the oil is hot enough. Carefully drop the lentil cakes into the oil and fry for four to six minutes until golden and cooked. (You may have to do this in batches.)

• Remove with a slotted spoon and drain on kitchen paper before serving hot, sprinkled with sea salt.